Garters in Europe?

[Bart]

There were stories about red-sided garters establishing a population in southern Sweden, but it appears that it was more or less a myth.

Natrix has one gigantic advantage over Thamnophis, and that is an insensitivity to thiaminase. Most of our streams and lakes are filled with cyprinids.

Wow, I didn't know, that grass snakes are immune to thiaminase! Are you sure about that?